162 U.S. NATIONAL MUSEUM BULLETIN 2 27 



rows of larger paragnaths followed by several rows of small ones, diminishing 



in size posteriorly N. (Nereis) pelagica (p. 179) 



Parapodial ligules triangular to conical, gradually tapering to a broad tip 

 (fig. 42c). Body usually transversely banded (may be faint or absent in 

 young specimens). Paragnaths of areas vii-viii with continuous row of 

 larger paragnaths followed by a wide band of small subequal ones. 



N. (Nereis) zonata (p. 181) 



Nereis (Neanthes) arenaceodonta Moore, 1903c 



Figures 44z, 45e 



S-pio caudatus Delle Chiaje, 1822, pi. 28, figs. 10, 15; 1825, pp. 403, 432. Not 



(Savigny, ms.) Lamarck, 1818, p. 319. 

 Nereis (Neanthes) caudala Delle Chiaje, 1841, pp. 96, 104, pi. 102, figs. 10, 15. — 



Fauvel, 1923, p. 347, fig. 135, a-e; 1955, p. 7.— Herpin, 1926, pp. 18, 101, 



120.— Day, 1953, p. 425; 1960, p. 324. 

 Nereis arenaceodonta Moore, 1903c, p. 720, pi. 40, figs. 1-10. — Sumner, Osburn, 



and Cole, 1913, p. 620.— Benham, 1916, p. 134, pi. 46, figs. 1-3. 

 Neanthes cricognatha Knox, 1951, p. 217, pi. 45, figs. 6-8. 

 Neanthes caudata Renaud, 1956, p. 16, fig. 11. — Reish, 1957, p. 216, figs. 1-9; 



1959, p. 81.— Rioja, 1958, p. 255. 



Description. — Length up to 70 mm., width up to 4 mm., segments 

 up to 75. Prostomium (fig. 45e) about as long as broad, strongly 

 convex anteriorly. Tentacular cirri relatively short, longest reach 

 setigers 3-9. Parapodia (fig. Mi) relatively long, similar throughout 

 the length of the body. Notopodia with 3 ligules, upper one larger, 

 triangular; middle or presetal and lower ones subequal, pointed. 

 Neuropodia with 2 slender, pointed ligules, postsetal and subsetal. 

 Acicula colorless. Notosetae a fan-shaped bundle of homogomph 

 spinigers; both upper and lower groups of neurosetae homogomph 

 spinigers and heterogomph falcigers with relatively long hooked blades. 

 Dorsal and ventral cirri subequal, shorter than the upper notopodial 

 ligule. 



Proboscis (fig. 45e) \\dth brown curved jaws, each with 6-15 teeth. 

 Paragnaths of oral or basal ring (areas v-viii) forming a continuous 

 broad band; area i, an elliptical group of denticles; area ii, crescentic 

 groups; area iii, an elongate oval group; area iv, triangular groups. 

 Color, in life: white, transparent, pale yellow or bright pink with 

 brownish or purple (Fauvel) ; color, preserved: splotched with brownish 

 or bluish on prostomium and first few segments, in bases of parapodia 

 and ligules, the pigment may be irregularly scattered in the body or 

 may be somewhat banded. 



Biology. — Found at low water in muddy sand and sand, on Diopatra 

 tubes, in mussel beds, and with sponges and algae. Found on drifting 

 algae. Dredged on bottoms of gravel, mud, sand, among tunicates (as 

 sandy Amaroecium). According to Plerpin (1926), it is found on the 

 lower side of rocks covered with the green alga Enteromorpha, where 

 these rocks rest on muddy sand and even quite compact clay; it 

 constructs tubes with thin walls but often incrusted with mud and 



